1. Field of the Invention
The present invention relates to a foodstuff containing a moist meaty filling for use in connection with shelf stable biscuits. The foodstuff containing a moist meaty filling has particular utility in connection with a gel in a recessed cavity upon a biscuit.
2. Description of the Prior Art
Foodstuffs containing a moist meaty filling are desired by pets across the country, especially dogs. Dogs consume biscuits by the millions each year. The biscuit provides a crunchy food often as a snack or treat. When chewed, the biscuit crumbles and the pieces assist in cleaning a dog's teeth. Dogs also like wet food, commonly served from a can. Wet food usually has a meaty taste and consistency to satisfy a dog's instinctual need for meat. Combining meaty wet food with a dry biscuit in an un-refrigerated form has challenged the pet food industry.
The use of shelf stable meaty products is known in the prior art that illustrates alternative methods for producing a combination product of dry biscuit and meaty filling, dry and wet phases respectively. Many alternate methods combine the soft and hard foodstuffs into a single unit. Numerous methods of co-extrusion exist as well as encapsulating and coating techniques for combining the soft and hard foodstuffs.
The prior art demonstrated both pet food and treat application as well as human food applications. For pets, a wide range of two phase products has been demonstrated where both phases remain at their natural moisture levels. For example, U.S. Pat. No. 3,922,353 to Bernotavicz discloses a shelf stable high moisture product. Made by a typical co-extrusion technique, the product includes a filling containing up to 50% moisture and a water activity exceeding 0.9. The product has a cereal based outer shell baked and then partly dehydrated after extrusion. For preservation, the product maintains a low pH of approximately 3.9 to approximately 5.5 with up to 8% acid the in the cereal phase.
U.S. Pat. No. 4,276,311 to Burrows et al. shows another acid stabilized two component pet food. The '311 patent has solid protein pieces mixed in an aqueous gel with later bacterial growth utilized to lower the pH below 4.5 for long term stability.
Similarly, U.S. Pat. No. 5,695,797 to Geromini et al. teaches a co-extruded pet food with an outer casing and an inner filling. The outer casing has a moisture content between 20% and 40% while an oil based substrate composes the inner filling, representing 30% to 40% of the total volume. The high moisture level of the outer shell results in a total loss of crunchiness in a biscuit formed by this technique. A fat based filling on the surface of a biscuit causes wicking of the packaging and possible staining of rugs in a pet's home.
Similarly, U.S. Pat. No. 3,916,029 to Hildebolt discloses a center filled pet food with an outer pastry shell and a higher moisture inner filling. This co-extruded technique uses puts all of the desired salt from the formula and a majority of the soluble sugar fraction from the formula into the inner filling to allow a higher moisture phase on the inside of the product. After baking, the outside cereal shell has about 13.5% moisture and the inner filling has 20% to 25% moisture. However, the water activities of the two phases remain about the same and range between 0.82 and 0.83. As in Gerominin's '797 patent, the elevated moisture level in the outer shell results in the loss of crunch in the finished product.
Other techniques result in a two phase pet food system but rely on dehydration of both fractions for long term stability. One techniques appears in U.S. Pat. No. 4,190,679 to Coffee et al. that discloses a dual textured pet food product. This product relies on formulation and processing techniques that yield two different types of particles packaged together within the same foodstuff.
Similarly, U.S. Pat. No. 4,006,266 to Bone et al. offers a pet food with separate hard component pieces and soft component pieces mixed in a final blended product. This patent specified moisture levels in the range of 8% to 12% for the hard component and 10% to 14% for the soft component. However, the patent specified equal water activites for the hard and soft components that jointly ranged from 0.60 to 0.75.
Then U.S. Pat. No. 4,273,788 to Bone et al. again provides a mixture of hard and soft components of a pet food using slender strands to formulate a softer fraction. Again, both components had equal water activities that jointly ranged from 0.60 to 0.75. The Bone and Coffee patents disclose separate individual particles within the same ration and could produce a biscuit containing a meaty filling.
Another approach for a two phase system formulates a single dry phase and aligns the dry phase with an oil based secondary fraction. U.S. Pat. No. 6,117,477 to Paluch discloses a multiple component food product formed by co-extrusion of a dry outer phase surrounding an oil based inner phase. Paluch in U.S. Pat. No. 6,254,910 builds upon the '477 patent with a method to incorporate a process unstable ingredient into the inner phase. Both of Paluch's patents call for a moisture level of less than 15%.
Similarly, U.S. Pat. No. 5,695,797 to Geromini teaches a co-extruded pet food with a high moisture outer shell preserved by acid and a vegetable oil or fat based inner filling. As discussed above, in producing a biscuit with a meaty topping, these techniques would cause wicking in packages and stains upon rugs in pet homes because of the oily fat layer exposed upon the surface of the biscuit.
Then similarly in U.S. Pat. No. 4,508,741 to Corbett et al. describes a method for combining separate phases in a pet food by coating a farinaceous based core with two additional components to yield a final product with a glistening appearance. All phases dry during processing and yield equal moisture and water activity.
Similarly, U.S. Pat. No. 5,673,653 to Sherrill also teaches a dual phase product composed of rawhide wrapped around a sliced meat fraction. This dehydrated product has phases of similar moisture levels.
Similarly, U.S. Pat. No. 4,364,925 to Fisher has a unitized animal feed system with mixed structural fibers within a continuous matrix. As in Sherrill, the dehydrated phases have similar moisture content.
Similarly, U.S. Pat. No. 5,635,237 to Greenberg et al. shows a co-extrusion rawhide having both inner and outer cores of a rawhide fraction. Inclusion of rawhide further softens the inner core but the moisture levels of both phases remain nearly equal. These dehydration methods worsen the palatability in comparison to the present invention.
Then similarly, U.S. Pat. No. 6,238,715 to Baikie claims a gel filling deposited into the center of a sterilized animal bone. This technique predates the patents in the assignor's portfolio. While the two phases—filling and bone—have different moisture levels, moisture does not transfer between them due to the pure ash nature of sterilized animal bone.
Similarly, U.S. Pat. No. 6,277,420 demonstrates two phase systems for pet treats with one phase of intermediate moisture filling and the second phase of dehydrated or chopped and reformed rawhide. This patent had limited moisture migration but, the dehydrated fraction—the rawhide—did not contain any carbohydrate or soluble protein fractions. Therefore, the second phase has less tendency to collect moisture from a filling than a baked biscuit with soluble grain fraction.
Turning to human foods, two separate phases with different moisture levels form a single food item. Most of these dual phase foods require refrigeration or freezing during distribution and sale. In U.S. Pat. No. 4,574,690 to Chiao a method co-extrudes wrapped food products with separate phases. This method relies upon freezing the final product to maintain stability and to reduce moisture transfer between the phases.
Similarly, U.S. Pat. No. 5,525,366 to Zuckerman et al. shows a two part food product having an outer grain shell and an inner non-grain interior. The product is formed with primarily whole grains and while moisture levels vary between the two phases, commercial distribution requires a frozen product. Freezing of the product reduces the transfer of moisture between the phases.
Then in U.S. Pat. No. 4,847,098 to Langler, two different food textures have their water activities equalized to reduce moisture migration between the two phases. This patent teaches a dual textured food combining an outer shell fraction and a second fluid core portion. Though generally a gel, the core has a center filling of water in an oil emulsion. The water activities of the shell and core remain equal and range between 0.50 and 0.80.
Then in U.S. Pat. No. 5,455,059 to McFeaters fat free topping and filling for bakery items yield foods with two distinct textures and appearances for the same product. Patent '059 has fat free topping formula with 60% to 70% sugar and 7% to 12% converted starch to bind the product. A humectant like glycerol achieves a water activity below 0.70 in the topping. Though successful with bakery products, this topping has a shelf life of at most three months.
Lastly in U.S. Pat. No. 4,401,681 to Dahle a two phased food has reduced inter-phase moisture transfer. While reducing moisture transfer between two components, this patent has difficulties in adaptation to a filled biscuit. The claims indicate partial dehydration of the surface of the high moisture phase prior to contact with the lower moisture shell. A barrier layer forms upon providing dextrin to the high moisture component along with a hydrophilic polysaccharide gelling agent like pectin. Creating this barrier film at production speeds for economical manufacturing has high difficulty. This patent also teaches an outer dough phase ranging from 20% to 40% by weight and an inner jelly phases ranging from 25% to 60% by weight. The somewhat high moisture in the dough phase results in a fragile biscuit and loss of the crunch expected by the consumer for a pet biscuit. The patent omits discussion of water activity and apparently, the two phases likely have the same water activity. Yet, the filling can have a higher percentage of water because of the filling's high sugar content. Also, the shelf life for this dough and jelly product extends for only several months and not the year or more typical in pet foods.
While the above-described devices fulfill their respective, particular objectives and requirements, the aforementioned patents do not describe an foodstuff containing a moist meaty filling that allows a recessed cavity containing a shelf stable moist meaty filling.
Therefore, a need exists for a new and improved foodstuff containing a moist meaty filling that can be used for a recessed cavity containing a shelf stable moist meaty filling. This invention teaches a unique ability to maintain two separate phases of food in direct contact with each other and the phases contain significantly different moisture levels and A sub w levels. A sub w (water activity) measures the unbound, free water in a foodstuff available to support microbiological growth. Water activity arises from the partial vapor pressure of water in the foodstuff divided by the saturation vapor pressure of pure water at the same temperature. The product of this invention remains stable for up to eighteen months without a noticeable transfer of moisture between the dry biscuit and meaty filling. In this regard, the present invention substantially fulfills this need. In this respect, the foodstuff containing a moist meaty filling according to the present invention substantially departs from the conventional concepts and designs of the prior art, and in doing so provides an apparatus primarily developed for the purpose of a recessed cavity containing a shelf stable moist meaty filling.